Have you tried downloading with VPN? Your playstore account is linked in with your actual location through various apps that use location settings(I believe) and if you see your devices list it should also tell you which country they are each classified in. For example two of my phones can download the app (mostly used in us and uk)and the phones I keep here cannot. I downloaded the apps and sideloaded cracked versions that took care of whatever source code prevents them from working here(I guess. I didnt actally examine what the programmer changed) . And the voice is much more basic in that it tells you to "turn left in 500 ft" but no street names. It might just be a one off custom mod. I found it on android-zone, but the specific download is no longer available. These downloads often expire after a while for whatever reason. If you check back they might repost it. android-zone.ws/topic/63343-android-auto-v14096052-2386982-release/#comment-63662.
Note: I just checked the turn by turn with my usa loaded android auto and it does not work like you said. The side loaded one does work but now it has started crashing. If I turn off the 3g then it stops crashing, but then what's the point of trying to use maps without 3g. I guess I will have to try to find another work around. I don't care about the turn-by-turn because I only used it once, but I like having my Google now cards.